Semiconductor device and method for manufacturing semiconductor device

Abstract

In a semiconductor device including a crystalline nitride layer, in which diamond is used for heat dissipation thereof, it is an object of the present invention to suppress cracking of the crystalline nitride layer. The semiconductor device includes a layered body and a heat dissipation layer. The layered body includes a crystalline nitride layer and a composite layer. The composite layer includes a non-inhibiting portion which does not inhibit diamond growth on a surface thereof and an inhibiting portion which inhibits the diamond growth on the surface. A layered body main surface of the layered body has a first region in which the non-inhibiting portion is exposed and a second region in which the inhibiting portion is exposed. The heat dissipation layer is made of diamond, opposed to the main surface, adhered to the first region, and separated from the second region with a void interposed therebetween.

The invention claimed is: 
     
       1. A semiconductor device, comprising:
 a layered body comprising a crystalline nitride layer and a composite layer, wherein the composite layer has a non-inhibiting material which does not inhibit diamond growth on a surface thereof and an inhibiting material which inhibits the diamond growth on a surface thereof such that a main surface of the layered body has a first region which is the surface of the non-inhibiting material and a second region which is the surface of the inhibiting material, where the first region is flat; and 
 a heat dissipation layer made of diamond and formed on the main surface of the layered body such that the heat dissipation layer is adhered to the first region and separated from the second region with a void formed between the heat dissipation layer and the second region, and that the void is tapered from the second region toward a tip of the void that exists in the heat dissipation layer, wherein 
 the void is a first void, 
 the main surface of the layered body further has a third region in Which the crystalline nitride layer is exposed, and 
 the heat dissipation layer is separated from the third region with a second void extending from the heat dissipation layer to the third region. 
 
     
     
       2. The semiconductor device according to  claim 1 , wherein the non-inhibiting material is made of amorphous silicon. 
     
     
       3. The semiconductor device according to  claim 1 , wherein the inhibiting material is made of crystalline silicon, aluminum nitride, or diamond-like carbon. 
     
     
       4. The semiconductor device according to  claim 1 , wherein:
 the first region comprises a plurality of sub regions separated from one another, and 
 the heat dissipation layer is adhered to each of the plurality of sub regions. 
 
     
     
       5. The semiconductor device according to  claim 1 , wherein:
 the crystalline nitride layer has a main surface facing the heat dissipation layer, 
 the main surface of the crystalline nitride layer has a covered region covered with the third region and the composite layer, 
 the composite layer has a main surface facing the heat dissipation layer, and 
 the main surface of the composite layer has the first region and the second region. 
 
     
     
       6. The semiconductor device according to  claim 1 , wherein:
 the crystalline nitride layer is not exposed to the main surface of the layered body. 
 
     
     
       7. The semiconductor device according to  claim 1 , wherein:
 the crystalline nitride layer has a main surface facing the heat dissipation layer, and 
 the non-inhibiting material and the inhibiting material are formed on different regions on the main surface of the crystalline nitride layer. 
 
     
     
       8. A method of manufacturing a semiconductor device, comprising:
 a) preparing a crystalline nitride layer having a crystalline nitride layer main surface; 
 b) covering the crystalline nitride layer main surface with a composite layer comprising a non-inhibiting material which does not inhibit diamond growth on a surface thereof and an inhibiting material which inhibits the diamond growth on a surface thereof, thereby obtaining a layered body which comprises the crystalline nitride layer and the composite layer and has a layered body main surface having a first region which is the surface of the non-inhibiting material and is flat, and a second region which is the surface of the inhibiting material; and 
 c) depositing polycrystalline diamond on the first region by chemical vapor deposition method, to thereby form a heat dissipation layer made of polycrystalline diamond on the layered body main surface, such that the heat dissipation layer is adhered to the first region and separated from the second region with a void formed between the heat dissipation layer and the second region, and that the void is tapered from the second region toward a tip portion of the void that exists in the heat dissipation layer, wherein
 the void is a first void, 
 the layered body main surface has a third region in which the crystalline nitride layer is exposed, and 
 the heat dissipation layer is separated from the third region with a second void extending from the heat dissipation layer to the third region. 
 
 
     
     
       9. The method of manufacturing a semiconductor device according to  claim 8 , wherein:
 the non-inhibiting material is made of amorphous silicon, 
 the inhibiting material is made of crystalline silicon, 
 in b), the crystalline nitride layer main surface is covered with an amorphous silicon layer comprising a first portion, a second portion, and a third portion, and by irradiating the second portion with a laser beam having a first intensity and irradiating the third portion with a laser beam having a second intensity higher than the first intensity, the first portion becomes the non-inhibiting material, the second portion is changed into the inhibiting material, the third portion is removed. 
 
     
     
       10. The semiconductor device according to  claim 2 , wherein the inhibiting material is made of crystalline silicon, aluminum nitride, or diamond-like carbon. 
     
     
       11. The semiconductor device according to  claim 1 , wherein the first region constitutes a main surface of the composite layer. 
     
     
       12. The semiconductor device according to  claim 1 , wherein the first region and the second region constitute a same plane. 
     
     
       13. The semiconductor device according to  claim 1 , wherein the composite layer is formed by partially irradiating an amorphous silicon layer with laser beam.